I have my ducks, geese, chickens, and guineas all together. Mind you they have a coop that the chickens go in, but the ducks and geese don't when the weather is not bad. They have a fenced in area around the coop that is predator proof that they are shut in at night. Plus they have a truck topper that is open at both ends they can go into at night, the chickens don't go in there, I guess they know it's not for them. Other than that they free range all day and stick to there own groups. The pools are in the fenced in area, but not near the coop. My chickens are never messy because of the ducks and geese and I never see them fight or anything, they all have their tail . This is the way I have been doing things for years without any trouble. I think it just depends on your setup and if they are raised from babies together.
Good luck on what you decide